References

ANGEO

Annales Geophysicae

ANGEO

Ann. Geophys.

1432-0576

Copernicus Publications

Göttingen, Germany

10.5194/angeo-24-2169-2006

Ionospheric signatures of the low-latitude boundary layer under conditions of northward IMF and small clock angle

Pryse

S. E.

¹ Sims

R. W.

¹ ³ Moen

² ⁴ Oksavik

² ⁵

Institute of Mathematical and Physical Sciences, University of Wales, Aberystwyth, SY23 3BZ, UK

University of Oslo, Blindern, Norway

now at: Medical Physics Directorate, University Hospital of North Staffordshire, Stoke-on-Trent, UK

also at: Arctic Geophysics, The University Centre in Svalbard, Longyearbyen, Norway

now at: JHU/APL, Laurel, Maryland, USA

13 09 2006

24 8 2169 2178

2006

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

This article is available from https://angeo.copernicus.org/articles/24/2169/2006/angeo-24-2169-2006.html

The full text article is available as a PDF file from https://angeo.copernicus.org/articles/24/2169/2006/angeo-24-2169-2006.pdf

A case study is presented that concerns the footprints of the low-latitude boundary layer in the high-latitude ionosphere. The measurements were made near local magnetic noon in summertime under conditions of <i>B<sub>z</sub></i>>0 and small clock angle. Of particular interest are particle fluxes measured in the region by the NOAA-12 satellite that revealed energetic (>30 keV) electrons, characteristic of trapped particles, together with a population of softer precipitating magnetosheath particles. The particle energy-distribution was distinct from those identifying the central plasma sheet at lower latitudes. On its poleward side the layer extended to at least the latitude of the polar cap boundary as identified in ion flows and electron densities measured by the EISCAT Svalbard radar. It is proposed that the particles of the low-latitude boundary layer occurred on newly-closed magnetic field lines, which were formed by the closure of open polar cap field by lobe reconnection in both Northern and Southern Hemispheres.

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